The release candidate enables development of applications with PSR-7 (PHP Standards Recommendation), a set of HTTP message interfaces that provide contracts for interacting with HTTP requests and responses, URIs, and uploaded files, Zend said. It allows for writing of small, single-purpose libraries for the likes of cookie-signing and content negotiation, said Matthew O’Phinney, project lead for Zend Framework, in an email.

PSR-7 is giving rise to middleware, which is code that sits between a request and a response, he said. Developers can write reusable, Web-facing code that can be dropped into frameworks that consume middleware. Slim Framework v3, Expressive, and Relay are three such frameworks that have arisen, said O’Phinney. Expressive supports dynamic routing, dependency injection, templating, and routing. A stable release is planned within the next few weeks.

The specification came to be because both server-side frameworks and HTTP client libraries were creating their own, typically incompatible abstractions, O’Phinney said. “This made reuse between frameworks very difficult without bridge layers, which were often buggy or impacted performance.” Through type-hinting on PSR-7 interfaces, code can signal it's available for reuse between frameworks that work with PSR-7 implementations.

Recently acquired by Rogue Wave Software, Zend this week also said it was making its Zend Server 8.5 PHP distribution available on Google Cloud Platform to enable developers to build enterprise applications in the cloud. Zend Server is offered via the Google Cloud Launcher, for launching of software packages on Google Compute Engine, which runs virtual machines on Google’s infrastructure.